#!/usr/bin/python3
# -*- coding: UTF-8 -*-
"""
质量控制
"""


def average(values):
    """计算数字列表的算数平均值

    >>> print(average([20, 30, 70]))
    40.0
    """
    return sum(values) / len(values)


import doctest

doctest.testmod()


import unittest
class TestStatisticalFunctions(unittest.TestCase):

    def test_average(self):
        self.assertEqual(average([20, 30, 70]), 40.0)
        self.assertEqual(round(average([1, 5, 7]), 1), 4.3)
        with self.assertRaises(ZeroDivisionError):
            average([])
        with self.assertRaises(TypeError):
            average(20, 30, 70)

unittest.main()

